The present invention relates generally to electronic musical instruments having a keyboard for performing tone selection or generation, and more particularly to an electronic musical instrument which detects a key opereting or performance style employed for the operated key on the keyboard and controls a tone in response to the detected key operating or performance style.
It is commonly known that characteristics of a tone generated by a natural piano vary depending on a key depression velocity. To approximate such characteristics, electronic musical instruments are generally provided with a transfer switch or a two-make-contact switch of bowl-like shape for each key so as to detect a depression velocity of each operated key.
However, the conventional keyboards having the transfer switch or two-make-contact switch are designed to only detect an average velocity at which a depressed key moves between two points, and thus the key depression velocity is detected as being the same even when the key operating or performance style is changed from one to another. In other words, with the prior technique, differences in key operating styles such as staccato, tenuto and the like can not be reflected in tones to be generated. Key operating style may also be detected using initial-touch and after-touch information, but such an approach to detection key operating style is not necessarily preferable to keyboard musical instruments in that tone generation is appreciably delayed while waiting for after-touch information to be obtained.
In view of the above-mentioned problem, so-called "whole-stroke-sensing keyboards" which are capable of detecting varying stroke positions of a depressed key to thereby achieve finer tone control are proposed in, for example, U.S. Pat. Nos. 5,107,748 and 5,187,315 and Japanese Patent Laid-open Publication No. HEI 3-67299. Each of these proposed keyboards is designed to detect varying key positions throughout the entire stroke of a depressed key.
Further, U.S. Pat. No. 5,292,995 proposes an electronic keyboard musical instrument which performs tone control by the use of preceding depressed key data and after-touch detection information on a preceding depressed key.
However, with the prior art electronic keyboard musical instruments, it is very difficult to change characteristics of tone to be generated by varying key operating styles such as staccato, tenuto and the like. It is also difficult to detect the operating style of a depressed key and generate in real-time a tone signal well reflecting a detected key operating style.